Now the system is ready, only rest to make it bootable. With grub, append in /boot/grub/menu.lst
title ZeroShell
root (hd0,4)
kernel /isolinux/vmlinuz quiet root=/dev/ram2 ramdisk_size=131072 init=/bin/init
initrd /isolinux/initrd.gz
boot

i guess one just need to type grub and type it line by line?
but at line initrd /isolinux/initrd.gz it said “file too big to fit in memory”…